sem_unlink()

Destroy a named semaphore

Synopsis:

#include <semaphore.h>

int sem_unlink( const char * sem_name );

Arguments:

sem_name: The name of the semaphore that you want to destroy.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

The sem_unlink() function destroys the named semaphore, sem_name. Open semaphores are removed the same way that unlink() removes open files; the processes that have the semaphore open can still use it, but the semaphore will disappear as soon as the last process uses sem_close() to close it.

Any attempt to use sem_open() on an unlinked semaphore will refer to a new semaphore.

Semaphores are persistent as long as the system remains up.

Returns:

0: Success.
-1: An error occurred (errno is set).

Errors:

EACCESS: You don't have permission to unlink the semaphore.
ELOOP: Too many levels of symbolic links or prefixes.
ENOENT: The semaphore sem_name doesn't exist.
ENAMETOOLONG: The sem_name argument is longer than (NAME_MAX - 8).
ENOSYS: The sem_unlink() function isn't implemented for the filesystem specified in path.

Classification:

POSIX 1003.1 SEM

Safety:
Cancellation point	No
Interrupt handler	No
Signal handler	Yes
Thread	Yes